(a) Field of the Invention
The invention relates to an integrated form of a cooling fin in a heating body, and more particularly, to an integrated form applied for joining a cooling fin to a surface of a heating element that is formed by a ceramic resistor having positive temperature coefficients. The invention is especially suitable for applications in automobiles, or other heating bodies used in equipments having vibrating energy, so as to securely fasten the heating element and the cooling fin while also obtaining shock-absorbing effects and preventing dismantling of elements.
(b) Description of the Prior Art
Heating apparatus using ceramic resistors as heating members thereof, due to characteristics of the ceramic resistors as being temperature constant and having rapid heating speed without causing flint, are extensively used in heat wave producing applications in various transportation equipments or instruments, and household warming systems. In a prior heating body, a heating element and a cooling fin thereof are joined using mechanical press bonding and agglutination. Referring to FIG. 1, a heating element 1 has an electrode layer 11 at two sides thereof, respectively. Each of the electrode layers 11 is pressed against and conducted by the cooling fins 2, so as to conduct electricity and transmit heat waves. The cooling fins 2 applied with the electrode layer 11 are stabilized by a supporting plank 3 via an externally adjacent insulation layer 41. Through tension provided by a spring 4 between the supporting plank 3 and an outer frame 5, the cooling fins 2 are bi-directionally pressed against the two sides of the ceramic heating element 1. However, when the prior heating body formed using elastic press bonding is applied in an automobile, the heating element 1 and the cooling fins 2 are prone to be relative displaced owing to vibration energy of a traveling automobile or being located at a point of mechanical resonance.
There is a more advanced heating body formed by agglutination available on the market. Referring to FIG. 2, a heating element 1 is applied with a conductive layer 11. The conductive layer 11 is faced with wave bases of a cooling fin 2 formed in a sine wave structure, and is adhered by adhesive 6, such that the wave bases are in contact with a surface of the electrode layer 11 for conducting electricity and providing shortest heat transmission paths. Yet, the surface of the cooling fin 2 is a smooth surface, and an adhered plane thereof still forms a smooth plane having insufficient structural strength after being adhered by the adhesive 6. As a result, loosening and dismantling are similarly incurred accompanied with acceptance of vibration energy.
Again, a heating body having reinforced strength had become available. Referring to FIG. 3, an underside of a cooling fin 2 is plated with a tin layer 7. The tin layer 7 is made of a material that may be fused as a material of the electrode layer 11 of the ceramic heating element 1. It is to be noted that the heating element 1 has intrinsic mass and the tin layer 7 is a hard substance. As a result, when a heating body formed using the aforesaid method is applied in vibrating equipments such as automobiles, in which considerable energy formed while reaching a point of mechanical resonance is acted upon a joining plane thereof, interface substances between the tin layer 7 and the electrode layer 11 are likely to become crisp. In addition, stress generated from receiving vibrating energy is concentrated, so that the entire electrode layer 11 gets peeled off from receiving the stress, and the heating element 1 becomes exposed as shown in the diagram. Also, manufacturing process using the aforesaid method is rather complicated and inconvenient that production costs are relatively increased. Above all, during the peeling off process, short circuits and sparks are likely caused for that various materials used are all conductive.
In the view of the aforesaid shortcomings, the primary object of the invention is to provide an integrated form of a cooling fin in a heating body, and that the integrated form is capable of providing reliable joining strength. Wherein, elasticity of the aforesaid adhesive 6 is capable of absorbing vibrating energy, and three-dimensionally expanded adhering areas are formed at a joining plane of the aforesaid cooling fin 2. The three-dimensional spaces formed are for containing the adhesive, and larger ranges are provided for absorbing vibrating energy through elasticity of molecules of the adhesive 6, thereby ensuring joining and binding of various elements.